Echelon FTXL - Manual (Page 109)

FTXL User’s Guide 97
You do not generally need to modify the code that the LonTalk Interface
Developer utility generates (in FtxlDev.c) or the LonMemoryRead() and
LonMemoryWrite() callback handler functions (in FtxlHandlers.c).
The DMF Memory Window
To the network management tool, all content of the DMF memory window is
presented as a continuous area of RAM memory in the virtual DMF memory
space. The DMF memory space is virtual because it appears to the network
management tool to be located within the FTXL Transceiver’s native address
space, even though it is not. In the code that the LonTalk Interface Developer
utility generates, the content of the DMF memory window, which can be
physically located in different parts, or even types, of the host processor’s
memory, is presented as a continuous area of memory. Another part of the
generated code identifies the actual segment within the host memory that is
shown at a particular offset within the virtual address space of the DMF memory
window, and allows the DMF memory driver to correctly access the
corresponding data within the host processor’s address space.
Data that appears in the DMF memory window includes:
• The file directory
• The template file
• The writeable CP value files (if any)
• The read-only CP value files (if any)
Figure 12 on page 98 shows how the different memory address spaces relate to
each other.